Store version number in properties instead of generating Version class

.gitignore

@@ -17,4 +17,3 @@ PROB_LOGFILE_IS_UNDEFINED
 src/main/resources/build.properties
 config.groovy
 local.*
-Version.java

build.gradle

@@ -30,31 +30,17 @@ java {
   withJavadocJar()
 }
 
-jar {
-  manifest {
-    attributes 'Main-Class': mainClassName
+processResources {
+  inputs.property("project.version", project.version)
+  filesMatching("org/sablecc/sablecc/build.properties") {
+    expand(version: project.version)
   }
 }
 
-task writeVersion() {
-
-  doFirst {
-    def buildconstants_class = """
-package org.sablecc.sablecc;
-
-public class Version
-{
-  public static final String VERSION = "${project.version}";
-}
-"""
-    File f = file("src/main/java/org/sablecc/sablecc/Version.java")
-    f.delete()
-    f <<  buildconstants_class
-  }
+jar {
+  manifest {
+    attributes 'Main-Class': mainClassName
   }
-
-compileJava {
-  dependsOn = ['writeVersion']
 }
 
 publishing {

src/main/java/org/sablecc/sablecc/Version.java

+
+package org.sablecc.sablecc;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.io.Reader;
+import java.nio.charset.StandardCharsets;
+import java.util.Properties;
+
+public class Version
+{
+  public static final String VERSION;
+  static
+  {
+    final Properties buildProperties = new Properties();
+    final InputStream is = Version.class.getResourceAsStream("build.properties");
+    if(is == null)
+    {
+      throw new IllegalStateException("Build properties not found, this should never happen!");
+    }
+    else
+    {
+      try(final Reader r = new InputStreamReader(is, StandardCharsets.UTF_8))
+      {
+        buildProperties.load(r);
+      }
+      catch(final IOException e)
+      {
+        throw new IllegalStateException("IOException while loading build properties, this should never happen!", e);
+      }
+    }
+    VERSION = buildProperties.getProperty("version");
+  }
+}

src/main/resources/org/sablecc/sablecc/build.properties

+# The values for these properties are generated during the build.
+# See the configuration of the processResources task in build.gradle.
+version=${version}